Treating cellulose fibers with alkali metal hydroxide and copper-alkylolamine complex



Patented June 20, 1950 TREATING CELLULOSE FIBERS WITH ALKALI METAL HYDROXIDE AND COPPER-ALKYLOLAMIN E COMPLEX Thomas C. Whither, Elizabeth, N. .L, assignor to Chemical Laboratories, Inc., a corporation of New Jersey N Drawing. Application December 20, 1944, Serial N 0. 569,107

1'7 Claims.

This invention relates to the treatment of vegetable or cellulosic fibers and involves particularly the treatment of such fibers with aqueous solutions of certain copper compounds.

In my copending application Ser. No. 534,989, and now Patent No. 2,446,682, I .have described treatment of vegetable or cellulosic fibers with aqueous solutions containing copper as an alkylolamine-copper complex. Such solutions although they may contain a slight excess of alkylolamine over that required to retain the copper in solution were substantially devoid of alkali metal hydroxides such as sodium or potassium hydroxide. I have observed that the addition of such soluble alkaline compounds to the aqueous solutions of alkylolamine-copper complexes serves to increase or promote the action of these solutions on vegetable or cellulosic fibers.

For example, I have noted that treatment of cellulosic fibers with an aqueous solution of alkylolamine-copper complex and alkali metal hydroxide decreases, over that resulting from treating with an aqueous solution of alkylolamine-' copper complex alone, adsorption of dyes by the fibers and consequently a modification of the color of the dyed fibers. ticularly noticeable when the quantity of alkali metal hydroxide is sufilcient to furnish an aqueous solution of about 4 per cent concentration. Furthermore, subjecting cellulosic fibers to the action of an aqueous solution of the copper complex and the hydroxide and subsequently to the action of an aqueous solution of a bleaching agent yields fibers which exhibit an increased adsorptive power for dyes as indicated by the increased color of the dyed fibers over that of fibers which have been subjected only to a similar bleaching treatment.

If the concentration of alkali metal hydroxide is greater than about 4 per cent, then the solution of alkylolamine-copper complex may exert a mercerizing efiect, which increases with the concentration of alkali metal hydroxide. However, as indicated by the decrease in length (of yarn) and decrease in area (of cloth) this mercerizing efiect on the fibers is less than that secured with an aqueous solution of only alkali metal hydroxide but of the same concentration.

The above-mentioned effects as well as others which are describedherein have been obtained when vegetable or cellulosic fibers are treated according to my process. As will be seen from the disclosures, my invention comprises a process for treating cellulosic fibers whereby the depth or shade of color (after dyeing) may be altered or These effects are par-' modified. My invention also includes controlling (i. e., decreasing or increasing) the degree 01 mercerization of cellulosic fibers due to the action of aqueous alkaline solutions.

The alkylolamine-copper complex solutions suitable for my purpose can be prepared, for example, by dissolving acopper salt (e. g., the chloride, acetate or sulfate) in water and then adding an alkylolamine to the solution until a clear blue liquid is obtained. The depth of color, of course, will depend upon the initial concentration of the copper salt. Alkali metal hydroxide can be incorporated in such solutions either by dissolving the solid hydroxide therein or by admixing an aqueous solution of the hydroxide therewith. The resulting liquids will contain in solution not only the alkali metal hydroxide and the alkylolaminecopper complex .but also some uncombined alkylolamine and some alkali metal salt corresponding to the copper salt employed. Solutions which are substantially free of dissolved alkali metal salts can be prepared, for example, by precipitating the copper salt (after dissolution in water) as copper hydroxide, filtering and washing the latter with water, then dissolving it in an aqueous solution of alkylolamine, and as the last step dissolving the alkali metal hydroxide therein or admixing an aqueous solution of the alkali metal hydroxide therewith. Any other convenient or desirable method may be employed in the preparation of aqueous solutions of an alkylolaminecopper complex and an alkali metal hydroxide.

Treatment of the cellulosic orvegetable fibers with these solutions can be effected in any convenient manner. Immersion of the fibers in the solution is probably the most expedient method. However, any other procedure is applicable whereby the fibers are thoroughly impregnated or saturated with the solution of alkylolaminecopper complex and alkali metal hydroxide and maintained so for the appropriate or necessary period of time.

The concentration of the solution used in treating the fibers, the time or length of treatment as well as the temperature of treatment are factors which can be varied widely. The appropriate conditions for any particular lot of fibers can be determined readily by experiment. In most instances atmospheric or room temperature will be suitable. However, I do not wish to be limited to this particular condition as lower temperatures, say, 5 C., 10 C. or lower, as well as higher temperatures, e. g., 40 0., C. or 0., may be employed. Preferably the temperature does not exceed about C.

After being subjected to the action of the alkylolamine-copper complex solution, the treated fibers are separated therefrom, pressed or squeezed (if desired) to remove at least partially adhering or adsorbed liquid, and then washed successively with water, dilute aqueous acid, and water. After which the fibers are dried. Any acid which is water-soluble, forms water-soluble salts on interaction with the alkali metal hydroxide, alkylolamine and alkylolamine-copper complex, and does not affect the fibers is suitable. Possibly the most conveniently employed acids are hydrochloric, acetic and sulfuric acids. The concentration of the acidic aqueous solution need not be great, say 3 to per cent, or thereabouts, as only a small quantity of adsorbed reagents, in most instances, remain in the fibers after the latter have been washed with water.

The following examples will illustrate my invention. It will be understood that in each case the fibrous materials were treated suitably to remove sizing and the like before being subjected to the treatment described.

Example 1.-Copper sulfate (CuSO4-5H2O) was dissolved in water, sufi'icient triethanolamine was added to give a clear dark blue solution, and the latter then was diluted with water until its concentration was equivalent to 1 g. of the copper salt per 100 cc. The resulting liquid was divided into three portions, and to these portions were added sufficient sodium hydroxide to react with the dissolved alkylolamine salt and to give, respectively, solutions containing 1 per cent, 5 per cent and per cent free or uncombined alkali metal hydroxide.

In each of the solutions, at room temperature, was immersed a sample of bleached cotton cloth for 2 hours. Afterwards, each sample was removed, pressed to eliminate adsorbed and adhering liquid, and then washed successively with water, dilute aqueous hydrochloric, acid, and water, and then dried.

The area of each piece of cloth was measured before and after treatment, and any decrease or shrinkage in area-was taken as an indication of the degree of mercerization effected by the treatment. It was noted that the cloth treated with the solution containing 1 per cent sodium hydroxide exhibited substantially no shrinkage in area. On the other handfthe fabric which had been immersed in the liquid containing 5 per cent sodium hydroxide decreased 3.6 per cent in area, and the sample subjected to the action of the solution containinglO per cent alkali metal hydroxide decreased 6.6 per cent.

The above samples of treated cloth and also one of the original untreated bleached cloth were dyed separately, using in each instance a dye bath consisting of 40 parts of water to 1 part of cloth and 4 per cent (on weight of cloth) of a blue substantive dye. In each case, the fabric was placed in the bath at room temperature, and then the temperature of the bath was raised slowly to 60 C. over a period of 30 minutes and kept at 60 C. for minutes. Afterwards the temper.- ature of the bath was reduced slowly to room temperature. The samples of textile material were rinsed with cold water and air-dried.

It was noted that the dyed materials which previously had been treated respectively with solutions containing 1 per cent and 5 per cent sodium hydroxide were lighter in color than the untreated dyed material. These two treated fabrics, however, were approximately the same color. It was observed also that the cloth which "had I been treated with the solution containing 10 per cent alkali metal hydroxide was very decidedly the darkest in color.

Example 2.Unbleached cotton cloth was immersed at room temperature in a solution containing alkylolamine-copper complex and 1 per cent sodium hydroxide as prepared in Example 1. After 21 hours, the cloth was removed, pressed, and washed successively with water, dilute aqueous hydrochloric acid, and water and then dried.

This sample of cloth and also one of the untreated original material were subjected separately to a mild bleaching operation in which were employed 5 per cent (on weight of fabric) of sodium perborate and parts of water per 1 part of cloth. The textile goods were worked in the respective baths at room temperature for 10 minutes, the temperatures of the baths then was increased to 60 C. over a period of 30 minutes and kept at 60 C. for 30 minutes. After this treatment, the samples were washed well with water and dried. Both were considerably lighter in color and substantially the same color, though neither one was fully bleached.

These partially bleached samples were dyed in the following manner: A green vat dye (in paste form) was admixed with water in the proportion of 0.4 g. of dye to 200 cc. of liquid, and to this admixture were add-ed 1.5 g. of sodium carbonate and 3 g. of sodium hydrosulfite (NazSzOs) per 200 cc. of aqueous dye mixture. After the dye was reduced, each sample of cloth was immersed for 1 hour in 100 times of its weight of dye solution at room temperature. Afterwards the fabrics were removed from the liquid, exposed to the air until almost dry, then washed successively with water, warm dilute aqueous solution of soap, and water and then dried. In this instance the sample treated with the copper solution was dyed to a markedly lighter color, thus indicating that treatment with the copper solution had decreased the adsorptive properties of the fibers for vat dyes and that this decrease had not been affected by a mild bleaching operation.

Example 3.Copper acetate (Cu (CzHsOz') 'HzO) was dissolved in water and then diethanolamine was added until a clear blue solution was obtained. This was diluted with water until its concentration was equivalent to 2.5 g. of the copper salt per 100 cc. The resulting liquid was divided into three portions, and to these were added suflicient sodium hydroxide to react with the dissolved amine salt (from interaction between copper salt and alkylolamine) and to give solutions containing respectively 3, 6 and 12 per. cent of uncombined alkali metal hydroxide.

In each of the solutions at room temperature was immersed a sample of unbleached cotton cloth for 75 minutes. Afterwards, each fabric was removed from the liquid and washed successively with water, dilute aqueous sulfuric acid, and water and then dried. Measurements of the area of each sample before and after treatment showed that the cloth treated with the solution containing 3 per cent sodium hydroxide was substantially unchanged, that treated with the solution containing 6 per cent alkali metal hydroxide had shrunk 2.4 per cent, and the cloth subjected to the action of the solution containing 12 per cent sodium hydroxide had decreased 14.5 per cent.

For comparison, portions of the unbleached original cloth were immersed at room temperature and for 75 minutes in aqueous solutions corresponding respectively to those previously men- QLHRUH UUI tioned in this example and containing 6 per cent and 12 per cent alkali metal hydroxide but no alkylolamine-copper complex. That is, each solution contained sodium hydroxide, diethanolamine and sodium acetate in the same proportions in which they were present in the alkylolamine-copper complex solution. Afterwards, each sample was washed successively with water, dilute aqueous sulfuric acid and water, and then dried. In this case measurements of the areas of the fabrics before and after the mercerizing operation indicated that the cloth treated with the solution containing 6 per cent sodium hydroxide suffered substantially no shrinkage while that treated with the solution containing 12 per cent sodium hydroxide had shrunk 10.8 per cent.

In this instance, for the same concentration of alkali hydroxide, the aqueous solution containing dissolved alkylolamine-copper complex mercerized the cotton cloth to a greater degree as indicated by the shrinkage.

All of the above treated samples and one of the original cloth were dyed separately, using in each instance a dye bath consisting of 50 parts of water to 1 part of fabric and 2 per cent (on weight of sample) of a red substantive dye and 2 per cent (on weight of sample) of soda ash. The individual portions of textile material were in the respective dye baths for minutes at room temperature, and then the baths were heated to 60 C. over a period of 20 minutes and held at that temperature for 10 minutes, after which the baths were allowed to cool slowly to room temperature. The samples were removed,

rinsed once with cold water, and drained and airdried.

The two dyed samples which previously had been treated, respectively, with solutions of alkylolamine-copper complex containing 3 per cent and 6 per cent alkali metal hydroxide were lighter in color than the dyed original unbleached cloth. Of the two treated and dyed samples, the one which had been subjected to the action of the copper complex solution containing 6 per cent sodium hydroxide was the lighter in color. The portions of dyed fabrics previously treated with alkaline solutions from which was omitted the copper compounds were much darker in color than the dyed original cloth. That portion of material which had been mercerized appreciably (i. e., exhibited 10.8 per cent shrinkage) was the darker colored of these two fabrics and in fact was the darkest colored of all the dyed samples.

Of the two fabrics which had been mercerized (10.8 per cent and 14.5 per cent shrinkage, respectively) during treatment with the alkaline solutions, that pretreated with the aqueous alkaline alkylolamine-copper complex dyed to the lighter color, although both dyed samples were much darker in color than the dyed original cloth. In other words, even though the presence of alkylolamine-copper complex increased the degree of mercerization it also effected a decrease in the capacity of the cotton goods to take up dyes.

Example 4.Copper chloride (CuCl2-2HaO) was dissolved in water and 2-amino-2-methyl- 1,3-propandiol added until a clear blue solution was obtained. The latter was diluted with water until its concentration was equivalent to 5.4 g. of the copper salt per 100 cc. Sufiicient potassium hydroxide then was dissolved in the liquid to react with the amine salt and to furnish a solution containing substantially 3 per cent of the alkali metal hydroxide. Unbleached linen cloth was immersed for 2.5 hours in some of the solution at room temperature. Afterwards, the fabric was removed, washed successively with water, dilute aqueous hydrochloric acid, and water, and dried.

This treated fabric and also a portion of the original unbleached cloth were subjected separately to a bleaching operation at room temperature. Each sample was immersed for 1 hour in twenty times its weight of an aqueous solution of bleaching powder whose concentration was equivalent to 0.25 g. of active chlorine per liter. Next, the textile materials were soured for 30 minutes in dilute aqueous sulfuric acid and afterwards washed successively with water, dilute aqueous sodium thiosulfate and water, and then dried. The samples of cloth were much lighter and substantially the same in color, though neither was fully bleached.

These portions of linen then were dyed separately, using in each instance 50 parts of water to 1 part of cloth and 3 per cent (on weight of textile material) of a blue substantive dye. The fabrics were worked for 5 minutes in the dye bath at room temperature and then the temperature (of the bath) raised to 60 C. over a period of 20 minutes and maintained at 60 C. for 10 minutes, after which the bath was allowed to cool slowly to room temperature. The samples were removed, rinsed in cold water and permitted to drain and air-dry. In this instance the linen which had been pretreated with the solution of alkylolamine-copper complex dyed to a much darker blue color than the other sample.

Example 5.--Bleached (white) linen cloth was immersed for 21 hours at room temperature in a solution of alkylolamine-copper complex and alkali metal hydroxide as prepared in Example 4. At the end of this time the cloth was removed from the solution, washed successively with water, dilute aqueous sulfuric acid and water, and then dried.

This treated portion of fabric and also one of the original bleached cloth were dyed separately, using in each case parts of water to 1 part of fabric and 5 per cent (on weight of sample) of a blue substantive dye. The samples were worked for 15 minutes in the respective bath at room temperature, the bath then heated to 60 C. over a period of 15 minutes and kept at that temperature for 15 minutes, after which it was allowed to cool slowly to room temperature. The samples then were rinsed with cold water and air-dried.

The difference in color of the two dyed samples was very marked, the one treated with alkylolamine-copper complex being the much lighter in color.

Example 6.--The aqueous alkylolamine-copper complex solution employed in this instance was made with copper chloride (CuClz-ZHzO) and 2-amino-2-methyl-l-propanol and its concentration was equivalent to 2 g. of copper salt per 100 cc. To this was added suflicient potassium hydroxide to react with the amine salt and to furnish a solution containing substantially 2 per cent of alkali metal hydroxide.

Unbleached cotton cloth was immersed for 3 hours in a, portion of this solution at room temperature. Afterwards, the cloth was pressed to remove as much liquid as possible and then washed first with dilute aqueous hydrochloric acid and second with water. The treated material then was dried.

This sample and also one of the original unbleached material were dyed separately, using in each instance 80 parts of water per 1 part of cloth and 3 per cent (on weight of fabric) of a red basic dye. The samples were worked for minutes in the baths at room temperature, following which the baths were heated to 60 C. over a period of 20 minutes, held at 60 C. for 20 minutes, and then allowed to cool slowly to room temperature. The two portions of cloth were rinsed once with cold water and permitted to drain and dry, at room temperature.

Each sample was dyed to a good red color, but the one which had been pre-treated with the solution of alkylolamine-copper complex was very distinctly of a lighter shade.

Example 7.-In this case, the alkylolaminecopper complex solution containing potassium hydroxide as prepared in Example 4 was used. A sample of commercially bleached and mercerized cotton yarn was immersed in some of this solution at room temperature for 4 hours. Afterwards, the goods was washed successively with water, dilute aqueous acid and water in the manner previously indicated, and then dried.

This treated yarn and also some of the original bleached and mercerized material were dyed separately, using in each instance a bath consisting of 75 parts of water per 1 part of textile material and 4 per cent (on weight of cotton fibers) of a blue substantive dye. The fibers were worked for 10 minutes in the respective baths at room temperature, after which the baths were heated to 65 C. over a period of 30 minutes, maintained at that temperature 10 minutes, and then allowed to cool slowly to room temperature. The samples of yarn were removed from the baths, washed well with cold water, and allowed to drain and dry at room temperature.

Both samples were dyed to a good blue color, but the one which had been treated with the solution of alkylolamine-copper complex was very definitely of a lighter shade.

Example 8.Copper chloride (CuCl2'2H2O) was dissolved in water, ethanolamine added until a clear blue liquid was obtained, and the latter then diluted with water to give a solution whose concentration was equivalent to 2 g. of the copper salt per 100 cc. of liquid. To this solution was added sodium hydroxide in amount sufficient to react with the dissolved alkylolamine salt and to furnish a liquid containing substantially per cent of alkali metal hydroxide.

An aqueous solution was prepared which contained the same quantities and proportions of sodium chloride, sodium hydroxide and alkylolamine, as the above solution of alkylolamine-copper complex, but no copper compounds.

In a portion of each of the above solutions was immersed a Sample of bleached cotton yarn for 1 hour at room temperature. Afterwards, the samples of cotton were washed successively with water, dilute aqueous sulfuric acid and water and while wet were stretched to their original length and allowed to dry (by exposure to the atmosphere) in this stretched condition.

It was noted that considerably more mercerization occurred in the case of the yarn treated with the solution in which no copper compounds were dissolved, as indicated by the greater decrease in length of the skein due to treatment with the alkaline liquor and the greater force needed to stretch this yarn to its original length.

It was observed also that this yarn possessed a very marked sheen or luster which was not exhibited by the cotton treated with copper solution. This last-named difference was most noticeable, of course, with the air dried fibers.

These two mercerized samples and also one of the original bleached goods were dyed separately, using in each case '75 parts of water to 1 part of yarn and 7 per cent (on weight of fibers) of a blue substantive dye. The samples were worked for 10 minutes in the respective baths at room temperature, and then the bath temperatures were increased to 60 C. over a period of 20 minutes and kept at that temperature for 20 minutes, after which the baths were allowed to cool slowly to room temperature. The samples then were rinsed with cold water and air dried.

There was a very marked and well-defined gradation in the colors of the dyed samples. That of the original bleached yarn was the lightest, a darker color was displayed by the cotton material which had been treated with the alkaline solution of alkylolamine complex, and the deepest blue color was shown by the fibers which had been subjected to the action of the aqueous alkaline solution which did not contain dissolved copper compounds. The last-named textile material also exhibited a definite sheen or luster just as it did before the dyeing operation.

Example 9.An aqueous solution of alkylolamine-copper complex was prepared which contained l g. of copper acetate (Cu(C2H3O2)2-HzO) and 6 g. of 2-amino-2-methyl-1,3-propanediol per cc. of liquid. To this was added sufficient sodium hydroxide to react with the alkylolamine salt present in solution and to give substantially 2 per cent of uncombined alkali metal hydroxide.

Another aqueous solution was made which contained the same quantities and proportions of alkylolamine, alkali metal hydroxide and sodium acetate, but no dissolved copper compounds.

In each solution, maintained at a temperature of 60 to 65 C., was immersed a sample of the same unbleached cotton cloth for 1 hour. Afterwards, each sample was washed well with water, then with dilute aqueous sulfuric acid and lastly with water, and then dried.

These treated portions of cotton cloth were bleached separately by immersing each in 20 times its weight of an aqueous solution of sodium hypochlorite (containing 0.255 g. of available chlorine per liter) for '75 minutes at room temperature, then souring in dilute aqueous sulfuric acid, and afterwards washing successively with water, dilute aqueous thiosulfate and water, and dried.

These bleached samples were dyed separately, using in each instance a dye bath consisting of 75 parts of water to 1 part of cloth and 0.75 per cent (on weight of cloth) of a violet basic dye. Each portion of cloth was immersed for 10 minutes in the respective bath at room temperature, following which the temperature (of the liquids) was raised to 60 C. over a period of 30 minutes and maintained at 60 for 10 minutes. Then the baths were allowed to cool slowly to room temperature. The samples were removed, rinsed once with cold water and permitted to drain and air dry.

Both samples were dyed to a deep full color, though the color of the one treated with the solution of alkylolamine-copper complex was very distinctly darker than that of the other portion of cloth.

SREH Rec Example 10.-Crystalline copper sulfate (CuSO4-5H2O) was dissolved in water and the solution poured into aqueous sodium hydroxide, the quantity of the latter being slightly greater than that required to precipitate the dissolved copper salt as the corresponding hydroxide. The precipitate ,was filtered, washed well with water and allowed to drain. It then was removed from the filter, admixed with a small quantity of water, and triethanolamine was added to the mixture. The latter was allowed to stand over night, after which the resulting blue solution was filtered from a very small amount of insoluble material. The solution of alkylolamine-copper complex, was diluted with water until its cop-per concentration (by analysis) was equivalent to 5.73 g. of the copper salt per 100 cc. of liquid. The quantity of alkylolamine was equivalent to 10g. per 100 cc. of solution.

To 6 volumes of this copper solution were added 9 volumes of 33 er cent aqueous sodium hydroxide, and the mixture was stirred well. Bleached cotton yarn was immersed therein for 30 minutes at room temperature, after which the yarn was washed successively with water, dilute aqueous hydrochloric acid and water, and then dried. The decrease in length of the sample due to treatment was 23.9 per cent.

An aqueous solution was prepared analogous to the one of alkylolamine-copper complex and alkali metal hydroxide (just described) in that it contained the same proportions of alkylolamine and sodium hydroxide but no dissolved copper compounds. A sample of bleached cotton yarn (as used above) was immersed therein for 30 minutes at room temperature, after which it was washed with water and aqueous acid (as indicated above) and dried. This sample decreased 26.1 per cent in length because of the mercerizing treatment.

These two treated yarns were dyed separately, using in each instance 100 parts of water to 1 part of textile material and '7 per cent (on weight of yarn) of a blue substantive dye. The samples were worked for minutes in the respective bath at room temperature, and then the temperature (of the baths) was increased to 70 C. over a period of 30 minutes and maintained at that temperature for 5 minutes. Next, the baths were allowed to cool slowly to room temperature, after which the fibers were rinsed with cold water and permitted to drain and dry.

It was noted that of the two mercerized samples of cotton yarn the one pretreated with the solution of alkylolamine-copper complex dyed to the darker blue color.

As previously mentioned, the extent or degree to which the effects will be exhibited by the treated fibers will depend upon such factors as duration of treatment, concentration of alkylolamine-copper complex and of alkali metal hydroxide, and temperature of treating. The optimum conditions for any particular lot or sample of fibers can be determined readily by experiment. I do not wish my invention, therefore, to be limited to the specific conditions mentioned in the examples herein given.

The alkylolamines suitable for my purpose may be monohydroxy compounds, as for example, ethanolamine, or they may be polyhydroxy compounds, e. g., diethanolamine or triethanolamine. It should be noted also that such hydroxy alkylolamines may be either primary, secondary or tertiary amines. As they are both hydroxy and amino compounds they exhibit a high solubility in water, in fact in many instances are miscible in all proportions with that liquid. It is thus possible to prepare aqueous solutions of the corresponding copper complexes over wide ranges of concentrations.

Either bleached, unbleached or bleached and mercerized cellulosic or vegetable fibers can be employed. Fibers which have been mercerized but not bleached are applicable also. It is desirable, however, in all cases that the fibers be subtantially free of sizing and the like before they are subjected to treatment with the solution of alk'ylolamine-copper complex and alkali metal hydroxide.

What I claim is:

1. The process which comprises treating at a temperature of from 10" to C., undyed cellulose fibers with an aqueous solution of an alkylolam ine-copper complex and an alkali metal hydroxide as the essential ingredients, and washing said treated fibers with an aqueous solution of an acid forming soluble copper salt thereby removing substantially all adsorbed alkylolamine-copper complex and alkali metal hydroxide from said cellulose fibers.

2. The process which comprises treating at a temperature of from -10 to 100 0., undyed cellulose fibers with an aqueous solution of an alkylolamine-copper complex and an alkali metal hydroxide as the essential ingredients, the proportion of said alkali metal hydroxide being great enough to exert a mercerizing action of said fibers, and washing said treated fibers with an aqueous solution of an acid forming soluble .copper salt thereby removing substantially all adsorbed alkylolamine-copper complex and alkali metal hydroxide from said cellulose fibers.

. 3. The process which comprises treating at a temperature of from l0 to 100 C., undyed ellulose fibers with an aqueous solution of an alkylolamine-copper complex and an alkali metal hydroxide as the essential ingredients, the proportion of said alkali metal hydroxide being less than that required to exert a mercerizing action on said fibers, and washing said treated fibers with an aqueous solution of an acid forming soluble copper salt thereby removing substantially all adsorbed alkylolamine-copper complex and alkali metal hydroxide from said cellulose fibers.

4. The process according to claim 1 in which the alkali metal hydroxide is sodium hydroxide.

5. The process according to claim 1 in which the alkali metal hydroxide is potassium hydroxide.

6. The process which comprises treating undyed cellulose fibers with an aqueous solution of an alkylolamine-copper complex and an alkali metal hydroxide as the essential ingredients, maintaining the aqueous solution during treatment at substantially atmospheric temperature, and washing said treated fibers with an aqueous solution of an acid forming soluble copper salt thereby removing substantially all adsorbed alkylolamine-copper complex and alkali metal hydroxide from said cellulose fibers.

'7. The process which comprises treating undyed cellulose fibers with an aqueous solution of an alkylolamine-copper complex and an alkali metal hydroxide as the essential ingredients, maintaining the aqueous solution during treatment at a temperature of about 100 C., and washing said treated fibers with an aqueous solu- 11 tion ofan acid forming soluble copper salt thereby removing substantially all adsorbed alkylolamine-copper complex and alkali metal hydroxide from said cellulose fibers.

polyhydroxy alkylolamine-copper complexand.

an alkali metal hydroxide as the essential ingredients, and washing said treated fibers with an aqueous solution of an acid forming soluble copper salt thereby removing substantially all adsorbed alkylolamine-copper complex and alkali metal hydroxide from said cellulose fibers.

10. The process according to claim 8, in which the monohydroxy alkylolamine-copper complex is monoethanolamine-copper complex.

11. The process according to claim 9, in which the polyhydroxy alkylolamine-copper complex is diethanolamine-copper complex.

12. The process according to claim 9, in which the polyhydroxy alkylolamine-copper complex is triethanolamine-copper complex.

13. The process which comprises treating at a temperature of from to 100 C., undyed cellulose fibers with an aqueous solution of an alkylolamine-copper complex and an alkali metal hydroxide as the essential ingredients, washing said treated fibers with an aqueous solution of an acid forming soluble copper salt thereby removing substantially all adsorbed alkylolamine-copper complex and alkali metal hydroxide from said cellulose fibers, and bleaching said fibers.

14. The process which comprises treating at a temperature of from -10 to 100 C., undyed cellulose fibers with an aqueous solution of an alkylolamine-copper complex and an alkali metal hydroxide as the essential ingredients, the proportion of said alkali metal hydroxide being great enough to exert a mercerizing action of said fibers, washing said treated fibers with an aqueous solution of an acid forming soluble copper salt thereby removing substantially all adsorbed alkylolamine-copper complex and alkali metal hydroxide from said cellulose fibers, and bleaching said fibers.

15. The process which comprises treating at a temperature of from -10 to 0., undyed cellulose fibers with an aqueous solution of an alkylolamine-copper complex and an alkali metal hydroxide as the essential ingredients, the proportion of said alkali metal hydroxide being less than that required to exert a mercerizing action on said fibers, washing said treated fibers with an aqueous solution of an acid forming soluble copper salt thereby removing substantially all adsorbed alkylolamine-copper complex and alkali metal hydroxide from said cellulose fibers, and bleaching said fibers.

16. Cellulose fibers having the properties resulting from bleaching the product obtained by the process of claim 1.

17. Cellulose fibers having the properties resulting from bleaching the product obtained by the process of claim 9.

THOMAS C. WHITNER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 8,303 Mercer Aug. 19, 1851 2,072,870 Dreyfus Mar. 9, 1937 2,092,006 Moncrieff Sept. 7, 1937 2,092,009 Moncriefi et a1. Sept. 7, 1937 2,092,696 Dreyfus Sept. 7, 1937 2,148,659 Straub et a1 Feb. 28, 1939 2,189,918 Moncriefi Feb. 13, 1940 2,253,242 MacMahon et a1. Aug. 19, 1941 2,310,257 Ritter Feb. 9, 1943 FOREIGN PATENTS Number Country Date 479,341 Great Britain Feb. 3, 1938 485,920 Great Britain May 26, 1938 672,116 Germany Feb. 23, 1939 OTHER REFERENCES Matthews, Bleaching 1921, Chem. Cat. Co., N. Y., page 463. 

1. THE PROCESS WHICH COMPRISES TREATING AT A TEMPERATURE OF FROM -10* TO 100*C., UNDYED CELLULOSE FIBERS WITH AN AQUEOUS SOLUTION OF AN ALKYLOLAMINE-COPPER COMPLEX AND AN ALKALI METAL HYDROXIDE AS THE ESSENTIAL INGREDIENTS, AND WASHING SAID TREATED FIBERS WITH AN AQUEOUS SOLUTION OF AN ACID FORMING SOLUBLE COPPER SALT THEREBY REMOVING SUBSTANTIALLY ALL ADSORBED ALKYLOLAMINE-COPPER COMPLEX AND ALKALI METAL HYDROXIDE FROM SAID CELLULOSE FIBERS. 